write your own "hand-written" book based on CS guide, our wiki websites, exam papers available. Must contain (1) the detailed and structured explanation for each point on the syllabus, (2) examples, e.g. diagram, graphs, example code/algorithm, (3) related past paper questions and analysis. (4) your predicted exam question on this point.
HL: 14 + 6 + 5 = 25 hours
SL: 8+5 + 5= 20 hours